A variety of remote viewing devices are known for performing visual inspections in generally inaccessible test areas. Borescopes, endoscopes and laparoscopes are examples of remote viewing devices that incorporate a small light-gathering device at the distal end of an elongated inspection tube that is inserted through a small opening to reach a remote viewing area. The light-gathering device may be a fiber optic cable that transmits the gathered light through the inspection tube to a receiving device at the proximal end of the inspection tube, or it may be a camera that transmits a video signal through the inspection tube to a display located remote from the viewing area.
U.S. Pat. No. 5,373,317, incorporated by reference herein, describes a borescope that may be used for inspecting restricted areas of a component such as a turbine or electrical generator without necessitating the disassembly of the component. The borescope of the '317 patent includes a hand-held control unit incorporating a joystick that functions to control an articulated tip at a distal end of an insertion tube. The control unit also includes a video display device for providing images of a test area collected by a video camera forming part of a viewing head attached to the articulated tip. A light source provides light to the test area via a fiber optic bundle that passes through the hand-held control unit and the insertion tube to the viewing head. The servomotors that move the articulated tip in response to control of the joystick are also mounted within a proximal end of the control unit to provide a balanced construction to the hand-held control unit.